Wheel with elastic nave for steam or gas turbines and turbo-compressors.



IVI. LEBLANC.

WHEEL WITH ELASTIC NAVE FOR STEAIVI 0R GAS TURBINES AND TURBO COMPRESSORS. APPLICATION FILED AUG.I8| 1911.

@EL CRAM Patented Mar. 14, 1916.

5 SHEETS-SHEET' l.

IVI. LEBLANC.

WHEEL WITH ELASTIC NAVE FOR STEAM 0R GAS TURBINES AND TURBO COMPRESSORS.

APPLICATIN FILED AUG.I8, I9II.

nu Il 9 1 4, l m D d 9.. T E E H A s T E E H s 5 l/I//T/VSSESI l M. LEBLANC. WHEEL WITH ELASTIC NAVE FOR STEAM 0R GAS TURBINES AND TURBO COMPRESSORS.

` APPLICATION FILED AUG.I8| 19H.

1,175,460. j Patented 1111.111916.

5 SHEETS-SHEET 3.

H/S A TMR/MEV /A/ me 7'.

THE COLUMBIA PLANUURAPH 50 wAshlNToN, D. C.

M. LEBLANC.

WHEEL WITH ELASTIC NAVE FOR STEAM 0R GAS TURBINES AND TURBO COMPRESSORS.

APPLICATION FILED AUG. I8. I9II.

Patented Mar. 14, 1916.

5 SHEETS-SHEET 4- THE COLUMBIA PLANDGRAPH co., WASHINGTON, D. c.

IVI. LEBLANC.

WHEEL WITH ELASTIC NAVE FOR STEAM 0R GAS TURBINES AND TURBO COMPRESSORS.

Patented Mar. 14, 1916.

APPLICATION FILED AUG.|B, 1911.

5 SHEETSWSHEET 5.

WWA/E555 THE COLUMBIA PLANOGRAPM Co.. WASHINGTON, n. c.

iiNrr-nn srnans Parent ernten.

MARIGELEBLANC, or PARIS, FRANCE, nssIcNoR To smit. ANONYME POUR. LEXPLOL TATXON mas PRocE'Ds WEsTINGHoUsE-LEBLANO, OP Paars, PneNcn.

VHEEL VITH ELASTIC NAVE FOR. STEAM 0R GAS TURBINES AND TURBO-COMPRESSORS,

Specification of Letters Patent.

Application led August 18, 1911. Serial No. 644,780.

To all yzii/wm t may concern.'

Be it known that I, MAURICE LEBLANC, a citizen or subject of the Republic of France, of 45 Rue de lArca-dc, Paris, France, have made a new and useful Invention in `VVhe-els with Elastic Nave for Steam or Gras Turbines and Turbo-Compressors, of which the following is a specilication.

The elastic nave construction, the object of this invention, allows'of a rigid shaft being used for turbines and turbo-compressors having ka multiplicity of wheels.

The present invention will be described with reference to the accompanying drawings, in which-` Figure 1 is a diagrammatic figure indicating theoretically the relative positions of the center of gravity G of the wheel, of the center oty the gure or nave r and of the center of rotation O, Fig. 2 is a longitudinal section oi the whole appa atus, Fig. 3 is a cross section on line Y-Y in Fig. Q., Fig. -f'l is a cross section on line Z-Z in Fig. 2, Fig. 5 is a sectional view of the casing C, Fig. 6 is a longitudinal section, showing a modified apparatus wherein the springs in Fi 1 a re replaced by caoutchouc rings, Fig. 7 is a cross section on line X-X in Fig, 6,

Fig. 8 lis a sectional view representing the` having four wheels constructed accordingl to this invention, coupled directly to a turbine with three wheels of the same kind.

For the better understanding of the invention, some matters of a technical character will be first considered which relate to the criticalspeed of a turbine shaft and to the position of the center of gravity of a wheel with` respect to the center oi' the ligure or nave and the center ci' rotation of the wheel, 'Y

Then a turbine shaft supports several wheels it should be flexible, but then there is tliediiliculty that the shaft acquires as many critical speeds as Wheels, these critical speeds increasing with the number of wheels. It is necessary to give the shaft such a liexibility that under the weights of the several wheels it will acquire an inadmissible delection. To obviate this drawback, a rigid shaft can be used and each wheel be provided with springs, the springs of one wheel acting independently from those of another; the wheel naves are then secured to the rigid shaft by an elastic connection.

It is known, moreover, that if the center oi* gravity G ot a wheel be at a certain distance -from the geometric center of the nave, as long asthe speed of rotation Q0 is less than the critical speed wc, the geometrical center of the nave r is nearerthe axis of rotation than the center of gravity G; on the contrary, if fw be greater than we, the center of gravity Gr is between the axis ot' rotation and the geometrical center r (Fig. 1). y

It' the distance between the center of gravity G and the geometrical center r be termed the eccentricity then when center r is at a distance"l from the axis ot rotation O greater than the eccentricity the center of gravity Gr can be brought between the axis and the center r by turning the wheel through 180o around its geometrical center and so G will be altered to G1. The nave, the object of this invention, is constituted to permit this rotation around the center of the figure, and that in an automatic manner, by means ot' guard plates contacting with two wheels D D, constituted by peripheral projections on the casing C which cause the turbine wheel A to slide with respect to the casing C which carries it. ln fact, as the speed increases, so the pressure at the point of contact also increases, and it will not be long in overcoming the friction against the nave; the wheel A will slacken in its movement and will slide on casing C by turning around the geometrical center r (Fig. 1) g it will cause the center of gravity G to turn about point r and will tend to bring it between points r and i); a moment arrives when the retarding forces due to the springs R R surpass the centrifugal force and the contact of the nave and guide rings will cease, but free to recur if the critical speed be not again exceeded at this moment. The drive on the shaft will be eliiected simply by friction, which increases with the speed.

Patenten Mar. ia, reis.

rlhe turbine wheel is mounted on a rigid shaft turning around axis O O; the nave B is hollow and rests on y'a cylindrical casing ,Y

C around Vvwhich it can turn. rIhis casing has two series of peripheral projections constitutino two drums or wheels D D rovided with sockets for the reception of the ex- Ytremities of the springs R, so that they can be independently displaced. vThe other extremities of the springs are invariably connected with the shaft. These springs are straight and are radially directed so that centrifugal force may not deform them.

Each of them consists of arbundle of very thin strips for blades, retained in'position by the recesses or sockets E E. On the exterior face of the casing C are arranged diametrically opposed recesses F F in which' are fixed with some little play metal tongues i or feathers. rlhese are retained against thek interior face ofy the nave by centrifugal force, the pressure being proportional tothe square of the speed of rotation.` The fric! tion at starting can be increased by bending these tongues like a spring. y

The nave is moved onlyb'y friction. At the moment of starting, this friction is due only to the weight of the wheel A, then as the vspeed increases the pressure exerted by the metal tongues increases.

The overhanging projections of the wheels D surround two fixed guard rings H and I which limit the displacements of the wheelsV with respect tothe axis ofrotation. These guide rings allow an amplitude of deforma tion greater than the eccentricity of the center of gravity ofthe wheel with respect tov the center of the ligure. Y

In a state of rest, the springs are flexedv merely under the weight of the wheel. They should be disposed in suflicient number for the flexure to be independent of the angle through' which the shaft is turned.- The v direction of these springs should vbe such i' e the eccentricity). The result is exactly as that one can, by actingA on the nave, describe Y about the geometrical `center around the axis of rotation O O, ya circleof radius at least equal to the fiexure -lthe eccentricity (thel distance between the geometrical center and the 'center of gravity). The play allowed between the overhanging extensions of the wheels D D and the guard rings should be equalto f-l-e, (7 being the llexure,

The type of spring may be varied pr0-V llatter are slid.

vided the centrifugalforce does not tend to` break them. In Figs. 6 and 7, the springs the shaft and the casing C which is disposed as described above. The cylindrical extensions of the casing C, constituting the wheels D D, turnvin the interior of the xed guard rings H andV I. Y

When wheels are carried by anindeforinable axis, they can be increased in number without ltheir reacting the one on another, that is to saytlie springs of one, in bending, cannot transmit any strain to the springs of another. rllhe kuse of thesewheels having flexible naves allows ofk steam or gas turbines or turbo-compressors with multiple wheels, being run zit-speeds of several hundred turns per second, which has not up to the present time beenv possible with single wheel turbines. By -way'of examplerthere is shown in Fig. 13 a turbo-compressor of thenew system with four wheels lcoupled directly with aturbine yof the newk system having three wheels.V `1 i i Thepresent invention allows, besides the elastic nave, a particular system lof blades forturbo-compressors, which, by reason of.

their lightness, render the reactions of the springs of each feeble. 4. A

rfhe blades ofthe turbo-compressor wheels are constituted by radially arranged metal blades connected to the nave in any suitable way.r In Fig. 4l, by way of example, they areV attached by dovetail joints. The thickwheel ron. the shaft veryl ,ness ofthese blades is at first constant-then VAit increases from periphery' toward the cenf ter ;V the strain per unit of surface, thus remains-constant. l v c The density of a gas being always low and the tangential force exerted on the blades small, they can be veryslight'at their extremities and therefore very light and flexible, which allows the centrifugal force to maintain them' radially directed. Blades ofwood or rubbered bands of fabric can be used; the very light organic fibers withstand Vbetter the effects of centrifugal force. Y Fig. 8 shows how the Vbands are assembled. Strips of material of successively decreasing length, but of the saine width, are superposed one over the other, so that the two exl tiemities of eachstrip are at equal distances from theends of the longest strip, and the strips are then glued or united together'. They are wrappedv around a cylindrical rod L. The rod 'and strips are yplaced in a metalk sheath N and then vulcanized. On the periphery of the nave slots are made corresponding to the sheaths N into which the As a second application of the present invention, an arrangement of turbine arms will be described. j

To resist the action of the `centrifugal force, insteadof fixing the different buckets on one and the same disk, each bucket is connected to the nave by a separate rod. Each rod is made solid and of uniform strength, the diameter of any section of the rods being equal to the thickness of the disk, that thickness being taken parallelto the axis andat the same distance fromcthe axis as the section of the rod. As the section of a rod-varies as the square of its diameter, then with equality of stress a tangential speed can be transmitted 2 times greater to the rod than to the disk. ,But if each bucket is connected separately to the disk, it is advantageous to reduce as much` as possible the number of buckets, and to use buckets of the kind represented in Fig. 10, arranged as shown in Figs. 11 and 12.

Having thus described the nature of my said invention and the best means I know of carrying the same into practical effect, I claim: y f n l. An elastic nave constructionfor wheels of machines of the character described ernploying a plurality ofwheels mounted on one and the same rigid shaft and comprising a seating fixed to the rigid shaft, a circular casing supporting the nave of the wheel, adapted to be operated by the friction of parts interposed between the casing and the nave and to move eccentrically with respect to the rigid shaft, an` elastic connection connecting the seating to the casing and aipair of wheels constituted byperipheral projectionson the casing adapted tok abut against two guard plates and thereby cause the automatic sliding of the wheel with respect to the casing.

2. An elastic nave construction for wheels of machines of the character described employing a plurality of wheels mounted on one and the same rigid shaft and comprising a seating fixed to the rigid shaft, a cirj cular casing supporting the nave of the wheel adapted to be operated by the friction of parts interposed between the casing and the nave and to move eccentrically with respect to the rigid shaft, two wheels consti-` tuted by peripheral projections on the casing and provided with sockets, springs connecting the seating to the casing having each one end fixed to the seating and the other end adapted to slide in said sockets so that the wheels may abut against guard plates and thereby cause the automatic sliding of the wheel with respect to the casing.

3. An elastic nave construction for wheels of machines of the character described employing a plurality of wheels mounted on one and the same rigid shaft and comprising a seating fixed to the rigid shaft, a circular casingfsupporting the nave ofthe wheel, adapted to be operated by the frictlon of parts interposed between the casing and the nave and to move eccentrically with` respect to therigid shaft, caoutchouc rings pierced with holes parallel to the axis kof rotation connecting the seating to the casing, peripheral projections on the casing constituting two wheels, adapted to cause the automatic sliding of the wheel with respect to the casing on abutting against constituted by the cylindrical projections on,

the casing adapted to cause the automatic sliding of the turbine wheel with respect to the casing on abutting against two guard plates, and a system of blades, for the wheel constituted by flexible members radially disposed and fixed to the nave of the wheel.

5: An elastic nave construction for wheels of machines of the character described employing a plurality of wheels mounted on one and the same rigid shaft and compris-y ing a seating fixed to the shaft, a cylindri-l cal casing supporting the nave of the wheel and adapted to be operated by the friction of parts interposed between thecasing and the nave, and to move eccentrically with respect to the rigid shaft, an elastic connection connecting the seating to the casing, two wheels constituted by cylindrical projections on the casing adapted to cause the automatic sliding of the wheel with respect to the casing, on abutting against two guard plates, and flexible blades constituted by rubbered strips 'of fabric fixed in slots formed in the nave.

6. An elastic nave construction for wheels of machines of the character described employing a plurality of wheels mounted on one and the same rigid shaft and comprising a seating fixed to the shaft, a cylindrical casing supporting the nave of the wheel and adapted to be operated by the friction yof parts interposed between the casing and the nave, and to move eccentrically with respect to the rigid shaft, an elastic connection connecting the seating to the casing, two wheels constituted by cylindrical projections on the casing adapted to cause the automatic sliding of the wheel with respect to the casing, on abutting against two guard plates, and blades for the wheel formed of straps or several bands of fabric folded one over the ico otheri Withthe short bands-on the outside,v and a. rod around which the bands are fold-.,.fed for'securing each blade so formed to the'v 7. An elasticnave construction for wheels of machines of the character described, em-

ploying a plurality of wheels mounted on one and the same rigid shaft andrcomprising a seating, rigidly'mounted on the rigid shaft, a circular casing` for supporting the nave of the wheel yieldingly supported" on Vsaid seating, and a nave surrounding; said casing" and operatively connectedthereto by meansof friction only.

8. An elastic Vnave construction for wheels of machines of the character described, comprising a seating rigidly mounted on a rigid shaft, a nave support surrounding the seating and movable eccentrically with relation thereto, means for yieldingly con'nectingther sea-ting to the support, a nave loosely mounted on the support, and means between the` nave and the support for rictionally connecting the-nave to the support. Y

' 9. An elastic nave construction orfwheels ofmachines'of the character described, comr-Y prising a seating mounted on a rigid shaft,

a nave support surrounding the seating and movableeccentrically with relation to vthe shaft, Va. nave loosely mounted on thefnaveVV support, and means responsive to centrifugalforce i'ior increasing the frictional en-v gagement' between the nave and the support Y Yproportionallyv to the `increased speed of the wheei. i .Y e

10.An elastic l nave construction for Copies of this patent may beV obtained forvveeents 'eaehpby addressing l VWashington,11C.

, scribingwitnesses.

wheels of machines of Vthe character de scribed, comprising a lseating'adapted to be y rigidly mounted on a rigid shaft, a nave surrounding the seating and movable eccentrically with relation to the mounting shaft,

Vand ymetallic plates'disposed radially between the seating and the' nave for yieldingly supporting the nave, the inner ends of said plates beingpsecured to the seating by means offa dovetail construction.

ll. A wheel oiE the character described,A

comprising a hub, blades'of extreme lightness so vlocated* on the hub, that the plane of each Vblade passes through the Yaxis oit' the `wheel, each blade being formed of' leather VVbands which extend axially with re-y y Maiiialicii icnieiaiiio.l V"Vitnesses: 'f

ALBERT ',DiiLfis,

" H, C.v COKE. f.

the ,Com/missioner of Patents,V 

